Abstract: A patch-type defibrillator electrode for direct contact with the heart has a thin, flat, flexible generally circular mesh or foil conductive member with a pattern of slits for enabling continuous contact with the three dimensional, time-varying heart surface topography. The slit pattern includes two pairs of non-intersecting semicircular slits oriented along mutually perpendicular axes, and interior portions of the conductive member are flexibly movable in a direction normal to the plane member and are flexibly tiltable about the axes to provide the conforming contact. The slits may also be radial slits which do not meet at the center so the leaves of conductive members are independently mobile with respect to every other leaf. A Dacron envelope having a thrombus formation inhibiting agent surrounds the conductive member including the peripheral edges to reduce the risk of tissue burning from current supplied to the center of the conductive member by an electrode lead.

Abstract: Self-contained, self-powered, flexible electrical control signal generating means are located in the right ventricle of a heart and generate electrical control signals solely by mechanical movements caused by actions of and conditions in the heart without any electrical connection to and supply of electrical energy from any other power source which electric control signals are transmitted to a control circuit system of an implanted control unit which control unit transmits an electrical signal to a stimulation electrode implanted in tissue at the apex of the right ventricle of the heart which stimulation electrode uses the electrical signal to stimulate the heart.

Abstract: There is disclosed a tachycardia control pacer in which there is generated a sequence of pacing pulses at intervals which are a function of the effective refractory period intrinsically associated with the rate of the patient heartbeats. If the tachycardia episode is not terminated, another sequence of pulses is generated; however, the rate of the new sequence is decreased if at least one unevoked heartbeat was sensed during the preceding pacing pulse sequence and the rate is increased in the absence of any unevoked heartbeat having been sensed during the preceding pacing pulses sequence. Also, in order to smooth the transition between the fast pulses used to terminate the tachycardia episode and subsequent beating in sinus rhythm, pacing pulses continue to be generated at increasing pacing intervals until they merge into standby pacing.

Abstract: A porous cardiac pacemaker electrode comprising a concavo-convex electrode cap having a plurality of apertures therethrough and an electrode shaft having a supporting edge formed thereon to which the concave surface of the electrode cap is joined. The porous cardiac pacemaker electrode is produced by deforming a platinum plate into a concavo-convex shaped cap member, forming a plurality of selectively spaced apertures through the electrode cap member to make the electrode cap substantially porous, forming an electrode shaft having a supporting edge, and joining the supporting edge of the electrode shaft to the concave surface of the electrode cap member.

Abstract: A cardiac pacemaker electrode including an electrode tip having an external surface with a concave region formed therein to increase the pacing impedance thereof. Further, the external surface of the electrode tip is roughened, for example by abrading with a jet of glass beads projected under pressure, to increase the microsurface area of the electrode tip and to reduce the sensing impedance thereof.

Abstract: A pacer which facilitates the measurements of both electrode impedance and stimulation threshold. When activated by an external magnet, a sequence of reducing-amplitude stimulating pulses is generated, with successive pulses in the sequence being separated by full-amplitude pulses. This pulse alternation scheme allows long test sequences, and therefore measurements with greater resolution, because full-amplitude pacing pulses are always present (even though at a slightly reduced rate). The reduction in amplitude of successive pulses is determined by the electrode impedance rather than being predetermined, and thus the examination of a skin potential recording allows electrode impedance to be determined along with the capture threshold.